The fire in the 1700 block of Margo Drive was reported at approximately 3:01 a.m., the fire dispatcher said.
Firefighters had the fire under control by 3:51 a.m., the dispatcher said.
About 30 firefighters from the Contra Costa County Fire Protection District responded to the fire and no injuries were reported.
The Red Cross was called upon to house two adults living in one of the homes, the fire dispatcher said.
